The present invention relates to a laser marking system, and in particular, to a laser marking system for applying a marking on a workpiece.
Workpieces, such as electronic components are generally engraved with marks indicating such as manufacturing No., production date and designation for identifying the origin thereof. Engraving has heretofore been achieved by applying an ink coated stamp to the electronic components. This method has disadvantages that a long period of time is required to exchange the stamps and various pattern masks should be prepared since an appropriate stamp is selected every time when the electronic components are changed.
A laser marking apparatus disclosed in Japanese Unexamined Patent Publication JP-A-60-174671 comprises a liquid crystal mask using a liquid crystal element as a pattern mask, which is disposed between a laser generator and a workpiece. The liquid crystal mask is irradiated with a pulse laser beam from a pulse laser generator while a voltage is applied to a pattern of a display of the liquid crystal mask. Only the pattern of the pulse laser beam which has passed through the liquid crystal mask will pass through a polarization plate and will impinge upon the surface of the workpiece to mark the pattern thereon. Another laser marker is disclosed in U.S. Pat. No. 4,818,835.
In order to mark the workpiece with a pattern by using a large marking system, it is necessary to increase the output power of the laser generator. Accordingly, there is a disadvantage that a pulse laser generator having a high output.